1. Technical Field
The present invention relates to a liquid ejecting head and liquid ejecting device having a piezoelectric element causing a pressure change in a pressure generating chamber communicating with a nozzle opening and having a piezoelectric layer and an electrode that applies a voltage to the piezoelectric layer, and the piezoelectric element.
2. Related Art
A piezoelectric actuator for a liquid ejecting head may use a piezoelectric element configured by interposing a piezoelectric layer made of piezoelectric material showing an electromechanical transduction function, for example, crystallized dielectric material, between two electrodes. As a representative example of the liquid ejecting head, there is an ink jet recording head in which a pressure generating chamber communicating with a nozzle opening discharging ink droplets is partially configured as a vibration plate so that the ink in the pressure generating chamber is pressed by transforming the vibration plate by the piezoelectric element to be discharged as ink droplets from the nozzle opening.
The piezoelectric material used for the piezoelectric layer (piezoelectric ceramics) of the piezoelectric element requires high piezoelectric features, as a representative example of such lead zirconate titanate (PZT) is given (JP-A-2001-223404).
However, from the viewpoint of environmental problems, piezoelectric material where the content of lead is suppressed is demanded. As a piezoelectric material not containing lead, there is BiFeO3 having a Perovskite-type structure expressed by ABO3. Here, A and B of ABO3 represent an A site and a B site, which are respectively sites where oxygen is 12-coordinated and 6-coordinated. However, the BiFeO3-based piezoelectric material has low insulation and tends to cause a leakage current. If a leakage current tends to occur, particularly when a high voltage is applied, cracks may tend to be generated, and so the material is not useful for the liquid ejecting head. Therefore, for example, piezoelectric material may have high insulation of 1×10−3 A/cm2 or less when a representative driving voltage of 25 V is applied.
In addition, this problem is present not only in the ink jet recording head but also in other liquid ejecting heads which discharge liquid droplets other than ink and the piezoelectric element used for equipment other than the liquid ejecting heads. Further, the leakage current problem causes a serious problem of the increase of energy consumption when the piezoelectric element is used as a sensor. For example, a low leakage current is desirable even for piezoelectric elements used for piezoelectric sensors, infrared sensors, temperature sensors and pyroelectric sensors to which a voltage of 1 V or less is applied.